Justification:
This species is listed as Least Concern, since it has not been declining by more than 25% in the last ten years, its European extent of occurrence (EOO) is larger than 20,000km² and its population size is probably larger than 10,000 adult individuals.

Occurs in Central Europe. It is absent from Ireland, Scotland, Scandinavia, the Netherlands, the Iberian Peninsula (except northern provinces), the Mediterranean islands (except Corsica and Sardinia) and most of the south of Italy. Found at altitudes from 100-2,000 m. This is a European endemic species.

Although widespread in Europe, this species is local and restricted to areas with sufficient habitat of good quality. Strong declines in distribution or population size of more than 30% have been reported from Luxembourg, Ukraine, United Kingdom. Declines in distribution or population size of 6-30% have been reported from Austria, Belgium, Czech Republic, Germany, Lithuania, Romania and Spain (data provided by the national partners of Butterfly Conservation Europe).

The Chalkhill Blue occurs on calcareous soil in dry and flower-rich places with a short vegetation. They seem to prefer sheltered places. Sometimes, populations can be extremely large which is especially obvious in the late afternoon when the butterflies come together to roost. Hundreds of butterflies can be seen, their heads pointing downwards into the vegetation, wings upright, the light-coloured underwings gleaming in the evening sun. Horseshoe Vetch (Hippocrepis comosa) is its only foodplant, the female laying her eggs on the leaves. The eggs hibernate. The caterpillars are attended by ants of the genera Myrmica, Lasius, Formica, Plagiolepis, Tetramorium, Aphaenogaster and Tapinoma. The Chalkhill Blue pupates in the litter layer. It usually only has one generation a year. Habitats: dry calcareous grasslands and steppes (35%), dry siliceous grasslands (13%), mesophile grasslands (13%), heath and scrub (5%), alpine and subalpine grasslands (5%), broad-leaved deciduous forests (5%).

All butterflies are collected to some extent, but only for the extremely rare species it can be a problem and the trade in Europe is generally at a low level compared to other continents. There is no specific trade information for this species.

This species occurs in a number of protected areas across its range. No specific conservation actions are needed at a European level, but in countries where the species is in decline important habitats should be protected and managed. The effects of conservation actions should be monitored by a Butterfly Monitoring Scheme.